A data bus can be utilized for interconnecting electronic devices such as television receivers, display devices, video-cassette recorders (VCR), direct broadcast satellite (DBS) receivers, and home control devices (e.g., a security system or a temperature control device). Communication using a data bus occurs in accordance with a bus protocol. Examples of bus protocols include the Consumer Electronics Bus (CEBus) and the IEEE 1394 High Performance Serial Bus.
A bus protocol typically provides for communicating both control information and data. For example, CEBus control information is communicated on a “control channel” having a protocol defined in Electronics Industries Association (EIA) specification IS-60. On an IEEE 1394 serial bus, control information is generally passed using the asynchronous services of the serial bus. Control information for a particular application can be defined using for example, Common Application Language (CAL) or AV/C.
Today, most A/V devices are controlled with a remote control (RC) unit. The protocol between the peripheral device and the RC unit is device specific such that each device comes with its own RC unit. Each such peripheral device interprets the key presses it receives via its direct link and carries out the corresponding actions.
In today's analog audio/video (A/V) cluster, controlling peripheral devices may include, but do not require, the activation of an On-Screen Display (OSD) mechanism on a display device (i.e., TV). The OSD of such A/V devices is generated in the peripheral or target device (e.g., digital VCR) and is output on the NTSC output of such devices the same way as any other video signal. Thus, no additional hardware or software is needed in either the peripheral or the display device. FIG. 1 illustrates an A/N system 10 having a VCR 12 and a display device 14 (e.g., television) that employs such a control methodology. Menus associated with controlling VCR 12 are generated by the VCR 12 and are provided to the display device 14 via the NTSC output of the VCR 12 as a composite video.
Unfortunately, to use the same approach (See FIG. 2) with a digital TV (DTV) as a display device 12′ is not practical since it would require the menus to be transported as MPEG-2 transport streams. Generation of such streams necessitates integrating an MPEG encoder 15′ into all peripheral devices which greatly increases the cost and complexity of such consumer electronic devices. Additionally, the GUI associated with the controlling device and peripheral device may differ and require the user to employ multiple remote control devices resulting in inconvenience for the user. Additionally, it is desired to improve the discovery process to provide on screen displays that facilitate user control of a system comprising multiple electronic devices.